In terms of diet, it is very simple. Eat breakfast and lunch normally, and do not eat snacks and drinks.
Dinner, because I have to study, I don't eat at all, for fear that you can't bite. You can try it first. If you can stand it and feel no pain, then you don't eat at all. If you think it will affect your study, add an apple. If not, add another cup of yogurt. In the third year of high school, the pressure is even heavier. I can eat some vegetables and fruits for dinner instead of staple food and starch.
If you persist in this way, you will definitely lose weight. Moreover, if you lose weight like this, you won't be hungry and feel refreshed every day.
When you start to lose weight, you weigh yourself and record a base. Don't weigh after you start. If you can, weigh yourself every two weeks or once a month, so that you will be happy to see that you have lost a lot of weight and will not be affected by things that usually care too much about your weight.